The present invention relates to a method for the finishing treatment of a fabric material or, more particularly, to a method for the finishing treatment of a fabric material by using a silicone-containing fabric finishing agent capable of imparting the treated fabric material with excellent touch feeling of softness and smoothness as accompanied by less significant troubles of yellowing of the treated fabric material than with conventional silicone-containing fabric finishing agents.
It is a conventional prior art method widely under practice that various kinds of fabric materials are imparted with improved touch feelings of softness and smoothness by a finishing treatment using a silicone-containing fabric-finishing agent. The silicones as the principal ingredient in the prior art fabric-finishing agents include dimethylpolysiloxanes, epoxy-modified organopolysiloxanes and aminoalkyl-containing organopolysiloxanes, of which aminoalkyl-containing organopolysiloxanes are most widely employed in respect of the particularly excellent softness imparted to the finished fabric material as well as versatility thereof relative to the kinds of the fibers forming the fabric material. While the aminoalkyl groups contained in the aminoalkyl-containing organopolysiloxanes are not particularly limitative, the aminoalkyl groups of the most preferred types include 3-aminopropyl group of the formula --C.sub.3 H.sub.6 NH.sub.2 and 3-N-(2-aminoethyl)aminopropyl group of the formula --C.sub.3 H.sub.6 NHCH.sub.2 CH.sub.2 NH.sub.2 because a fabric-finishing agent containing an organopolysiloxane having these aminoalkyl groups imparts the treated fabric material with very excellent touch feeling of softness as is taught in Japanese Patent Publications 48-1480, 54-43614 and 57-43673 and Japanese Patent Kokai 60-185679, 60-185880 and 64-61576.
Though excellent in respect of the touch feeling of softness of the treated fabric materials, the fabric-finishing agents containing an organopolysiloxane having the aminoalkyl groups of the above mentioned types are not quite satisfactory due to a very serious problem that the fabric materials finished therewith sometimes cause yellowing when subjected to a heat treatment or dried under sunlight or in the lapse of time due to degradation of the amino groups presumably by the influences of heat or ultraviolet light eventually resulting in the loss of the softness. This problem is particularly detrimental against white-colored or light-colored fabric materials.
Various attempts and proposals have been made heretofore with an object to solve the above mentioned problem due to yellowing of the fabric material finished with an aminoalkyl silicone-based fabric-finishing agent of the above mentioned types, in which the aminoalkyl-containing organopolysiloxane is modified by the reaction with an anhydride or chloride of an organic acid disclosed in Japanese Patent Kokai 57-101076, with an epoxy compound disclosed in Japanese Patent Kokai 59-179884, with a higher fatty acid disclosed in Japanese Patent Kokai 1-306683 and with a carbonate disclosed in Japanese Patent Kokai 2-47371. Modification of the aminoalkyl groups is of course not ineffective, though insufficient, to solve the problem of yellowing of the treated fabric materials but is accompanied by a decrease in the effectiveness of imparting softness and smoothness to the finished fabric materials as compared with a silicone-based fabric finishing agent containing an organopolysiloxane having unmodified aminoalkyl groups.
Besides the types of the aminoalkyl groups, another important factor which influences the usefulness of an aminoalkyl-containing organopolysiloxane as the principal ingredient in the silicone-based fabric-finishing agent is the content of the aminoalkyl groups in the organopolysiloxane. For example, the aminoalkyl-containing organopolysiloxane having 3-N-(2-aminoethyl)amino propyl groups most widely employed in he prior art fabric finishing agents has an amine equivalent in the range from 1500 to 2000 g/mole because of the highest softness imparted to the treated fabric materials. The amine equivalent here implied is the amount of the organopolysiloxane in grams giving 1 mole of the amino groups --NH.sub.2 and imino groups --NH-- as a total. When the amine equivalent of the aminoalkyl-containing organopolysiloxane is increased, for example, in the range from 3000 to 4000 g/mole, the trouble due to yellowing of the treated fabric materials can be dissolved to some extent though at a sacrifice of the softness imparted to the treated fabric materials.